Testing of rod-like articles,such as cigarettes

ABSTRACT

WRAPPINGS OF CIGARETTES AND SIMILAR ARTICLES ARE TESTED BY CREATING A PRESSURE DIFFERENTIAL RADIALLY ACROSS EACH WRAPPING TO DETECT WHETHER OR NOT THE WRAPPING IS LEAKY. THE CIGARETTES ARE CARRIED IN FLUTES IN A CARRIER DRUM PAST CO-OPERATING CLOSURE DRUM WHICH ENCLOSES THE CIGARETTES IN THE FLUTES AT A TESTING POINT BETWEEN THE TWO DRUMS, AT WHICH POINT THE TWO DRUMS DEFINE A CHAMBER AROUND THE CIGARETTES TERMINATED AT THE ENDS OF THE CIGARETTES BY SEAL PORTIONS DEFINED PARTLY BY EACH OF THE DRUMS TO RESTRICT   COMMUNICATION BETWEEN THE INTERIOR AND EXTERIOR OF A CIGARETTE VIA THE OPEN ENDS OF THE CIGARETTE WRAPPING.

spr. 2s, 1971 D. w. B. MUIR ETAL 3,608,380

TESTING 0F ROD-LIKE ARTICLES, SUCH AS CIGARETTES Filed Jan. 30 1969 4 Sheets-Sheet 1 lli il Sept. 28, 1971 n. w. B. Mum Erm. 3,608,380

TESTING OF ROD-LIKE ARTICLES, SUCH AS CIGARETTES Filed Jan. 30, 1969 4 Sheets-Sheet 2 Spt. 28, 1971 D, w, B MUlR ETAL 3,608,380

y TESTING 0F ROD-LIKE ARTICLES, SUCH AS CIGARETTES Filed Jan. 30. 1969 4 Sheets-Sheet 5 f/ /Mw/ da Jim jZLM/M Sept. 28, 1971 i' D, w, B: MUIR ETAL 3,608,380

TESTING OF ROD-LIKE ARTICLES, SUCH AS CIGARETTES Filed Jan. 30, 1969 4 Sheets-Sheet 4 United States Patent O1 hee 3,608,380 Patented Sept. 28, 1971 3,608,380 TES'I'ING 0F ROD-LIKE ARTICLES, SUCH AS CIGARETTES Douglas W. B. Muir, Biggar, Scotland, and Eryk Stefan Doerman and Robert James Hayward, London, England, assignors to Molins Machine Company Limited,

London, England Filed Jan. 30, 1969, Ser. No. 795,279 Int. Cl. G01m 3/26 U.S. Cl. 73-45.1 10 Claims ABSTRACT F THE DISCLOSURE Wrappings of cigarettes and similar articles are tested by creating a pressure differential radially across each wrapping to detect whether or not the wrapping is leaky. The cigarettes are carried in flutes in a carrier drum past co-operating closure drum which encloses the cigarettes in the flutes at a testing point between the two drums, at which point the two drums define a chamber around the cigarettes terminated at the ends of the cigarettes by seal portions defined partly -by each of the drums to restrict communication between the interior and exterior of a cigarette via the open ends of the cigarette wrapping.

This invention relates to improvements in the testing of rod-like articles, for example cigarettes, having an airpervious filling' and an open-ended wrapping, and is particularly concerned with methods and apparatus for performing an air test on the articles to determine the condition of their wrappings as these are liable to have faults such as air leaks or excessive porosity.

U.S. Pat. No. 3,266,295 describes a tester in which the cigarettes are tested in turn by being confined in a chamber defined partly by a fluted drum and partly by a fluted part carried by a belt conveyor. Co-operatin'g parts of the drum and belt conveyor form seals around the ends of each cigarette to restrict communication between the interior and exterior of the cigarette via the open ends; While a pressure differential is created radially across the wraping (that is to say, a difference in pressure inside and outside the wrapping) by connecting to suction the chamber surrounding the cigarette, this chamber being terminated by the seal parts. An excessive leakage through any cigarette wrapping is reffected in a drop in pressure in a space communicating with one end of the cigarette, and this drop in pressure is used to operate an ejector mechanism which ejects the faulty cigarette.

U.S. patent application Ser. No. 643,571 filed on June 5, 1967, now Pat. No. 3,485,084, and assigned to the assignee of the present application on the other hand describes a tester which differs primarily in the fact that the cigarettes are carried in flutes in a drum which also carries a number of movable caps, one per cigarette, which complete the seals at the ends of the cigarettes, while the suction chamber for each cigarette is defined partly by the fluted dru-m and partly by a stationary member.

The present invention is also concerned with a tester for testing the wrappings of cigarettes and similar articles by creating a pressure differential across each wrapping to detect whether or not the wrapping is leaky. A tester according to the present invention comprises a rotary carrier drum which has circumferentially spaced axial flutes and which carries the cigarettes, one in each flute, from an input conveyor to an output conveyor, and including seal portions at the ends of the flutes to restrict communication between the interior and exterior of the cigarettes via the open ends of the cigarette wrappings during testing, characterised in that the cigarettes are carried by the carrier drum past a co-operating closure drum which rotates adjacent to the carrier drum, about an axis parallel to that of the carrier drum and at the same peripheral speed, and has circumferentially spaced closure parts which register with the flutes on the carrier drum and are so shaped that each closure part of the closure drum co-operates with a flute of the carrier drum to define momentarily a chamber around the cigarettes, terminated at or near the ends of the cigarette by seal portions defined partly yby the carrier drum and partly by the closure drum to restrict communication between the interior and exterior 0f the cigarette Via the open ends of the cigarette wrapping.

It should be appreciated that this invention is applicable to the testing of rod-like articles other than cigarettes, though this specification will for convenience be written in terms of cigarettes. Moreover, in the case of filter-tipped cigarettes the rod-like articles tested according to this invention may consist of two cigarettes joined to opposite ends of a double-length filter Vwhich is subsequently cut across the middle to form two separate filtertipped cigarettes.

Testers according to this invention are relatively simple and can be made effective and reliable.

The carrier drum and closure drum preferably both have circumferentially spaced axially-extending flutes, so that at the moment of testing of a particular cigarette, the cigarette lies partly in the flute in the carrier drum and partly in the flute in the closure drum. In principle, however, the flutes in the carrier drum could be deeper, and the closure drum could be formed without definite flutes.

Testing is preferably carried out by applying a suction to the space around the cigarette, the presence of a leaky Wrapping being indicated by a drop in pressure in a space at one end of the cigarette communicating with the inside of the cigarette. The suction is preferably derived from a suction chamber in the closure drum.

In a preferred tester according to the invention the closure drum is carried by a housing pivoted about an axis parallel to the carrier drum and closure drum axes to enable the closure drum to be swung away from the carrier drum, about the housing pivot axis, for inspection or for any other reason; the closure drum axis -is preferably at a higher level than the carrier drum axis, and the housing pivot axis is so positioned that the closure drum is held against the carrier drum by gravity during testing. Preferably the bearing mounting the closure in the pivoted housing allows the closure drum a slight freedom to swivel about an axis parallel to the common tangent to the closure drum and carrier drum to ensure that both ends of the closure drum are in rolling contact with the carrier drum.

There may be a single rotary drive input to the tester, this being transmitted to the carrier drum, while the closure drum is driven by virtue of carrying a gear wheel meshing with a gear wheel on the carrier drum. Preferably the number of teeth on each gear wheel equals the number of flutes on the corresponding drum, so that the gear wheels can be brought into mesh in any position and will automatically cause the flutes on the two drums to register with one another.

Examples of testers according to this invention are shown in the accompanying drawings. In these drawings:

FIG. l is an elevation of one machine;

FIG. 2 is a section on the line II-II of FIG. l;

FIG. 3 is a view similar to FIG. 2 on the line III-III in FIG. 1;

FIG. 4 is an enlarged fragmentary section on the line lV-IV in FIG. 2;

FIG. 5 is a diagrammatic outline (partly sectioned) of a second machine; and

FIG. 6 is a diagrammatic section on the line VI-VI in FIG. 5.

The machine shown in FIGS. 1 to 4 comprises a carrier drum 1 and a closure drum 2 both of which are fluted to accommodate cigarettes and are mounted for rotation in synchronism with one another so that successive ilutes of one register with those of the other to define at a testing point a succession of test chambers for the cigarettes. Suction for testing is applied from a suction chamber in the drum 2, being supplied through a hollow shaft 3 which communicates with a fan. The closure drum 2 and the supply duct are carried in a single housing 4 which is pivoted about the axis of the shaft 3 so that it can be swung upwards away from the carrier drum 1 to provide access between the drums. A clamp (not shown) can be operated to lock the housing in its up position.

A continuous stream of cigarettes is fed onto the carrier drum 1 from a belt conveyor 7 by means of a fluted suction-pickup drum 8 and is set down on the conveyor 7 by means of a uted suction-return drum 9. The cigarettes are retained in position in their flutes on the drum 1 between the testing point and the points of pick-up and return by pairs of guide rails 10 and 11 respectively.

The closure drum 2 has a series of radial passages 12 opening at one end into its flutes 13 and communicating at the other end with an internal suction chamber 14 through a xed guard ring 15 which is provided with an aperture 49 registering with the suction supply duct 3 to provide communication to the chamber 14, and with a port 50 to provide communication from the chamber 14 to each of the ilutes 13 in turn at the testing point by way of the radial passages l12.

The construction of the flutes of each of the two drums is shown in FIG. 2. In each drum there are two axially spaced sealing ribs at each end of each flute. In the drum 1 the ribs, indicated by the reference 16, are defined by the escalloped edges of four discs 17, 18, 19 and 20. Between the discs 17 and 18, and between the discs 19 and 20 there are air spaces 21, 22 which communicate with the middle of the carrier drum 1 which is open to atmosphere. Between the discs 18 and 19, in the neighborhood of the cigarettes, there is a centre portion 23 of the drum which is formed in its outer periphery with grooves shaped to conform with the cigarettes but with clearance so as to dene an approximately halfannular space with each cigarette.

The closure drum 2 is formed with utes which complete the suction chamber around each cigarette at the testing point. In this case there are semi-circular sealing ribs 26 which are dened by the escalloped edges of rings 27 and 28 each of which has a circumferential groove, 29 and 30 respectively, between the ribs 26. In the testing position these grooves 29 and 30 communicate with the air spaces 21 and 22 respectively to dene around the end of each cigarette an air ring at atmospheric pressure. Between the rings 27 and 28 the closure drum has a centre portion 31 which is formed with the radial passages 12 and in its outer periphery with the flutes 13 into which the passages 12 open. End pieces 32 and 33, which form part of the closure drum, roll on the rings 24 and 25 of the carrier drum 1. The closure drum is kept in rolling contact with the carrier drum by gravity. Alternatively the closure drum may be held just out of contact with the carrier drum by means of a stop (preferably adjustable) limiting clockwise movement of the housing 4 about its pivot axis.

The cigarette-facing periphery 34 of each rib 16 or 26 is semi-circular (see FIG. 4) and they are all of the same size which is chosen according to the size of the cigarettes which varies within a tolerance range. The peripheral faces 35 of the discs 17 to 20 and rings 27 and 28 in the regions between the flutes are curved about the centres of the respective drums so as to be in rolling contact or just clear of rolling contact. The radius of the peripheries 34 of the ribs 16 and 26 is chosen so as to leave a gap around the largest possible cigarettes of a certain nominal size, having regard to the tolerance on the diameter of the cigarettes. In an example, for cigarettes having a diameter of 7.88 mm. within a tolerance of $0.1 mm., the diameter of the peripheries 34 is 8.04 mm., with a tolerance of 10.02 mm. For tipped cigarettes, which are larger at the tipped end, the peripheries 34 are larger at one end than the other.

Thus, in the testing position, there is a pair of sealing ribs 16, 26 encircling each end of the cigarette. Between the ribs there are annular spaces 21, 22, 29 or 30 which are substantially at atmospheric pressure and which isolate the annular suction chamber around the cigarette from the spaces at the ends of the cigarette, so as to prevent a direct leak of suction, except through the cigarette wrapping.

Means are provided at the testing position to cornmunicate between an end of a cigarette and a stationary test device. These means comprise a sliding valve block 36 which is urged by a spring 37 into engagement with a manifold ring 38 on one end face of the carrier drum 1 and which has a flow passage 39 connected by a pipe 40a to a testing device in the form of a suction transducer 40 which generates an electrical signal related to the pressure at the end of a cigarette. The sliding valve block 36 is supported from a shaft 41 (FIG. 1), on which the drum 1 rotates, by a bracket 42. The manifold 38 is formed with transverse passages 43, one for each cigarette, to provide communication successively between the suction transducer and the ends of the cigarettes via passageways 45 and 46 (see FIG. 2). Between the passageways `43 there are passageways 44 (see FIG. 1);

these communicate with the air space 22 via 47 in the disc 20, as shown in FIG. 3, which is a radial section slightly oifset from FIG. 2 so as to pass through a passageway 44, By this means, as the carrier drum 1 rotates, the suction transducer is alternately connected with a cigarette subjected to suction in the testing position, and then with atmosphere.

The leading end 4S of the guide 11 extends up into the groove 29 in the ring 27 of the closure drum 2 to ensure that none of the cigarettes sticks in the flutes 13 after testing.

The closure drum Z is driven to rotate in synchronism with the carrier drum 1 by a gear 51 on the closure drum which meshes with a gear 51a on the carrier drum. On each drum the number of gear teeth equals the number of flutes, so that the gears can be brought into mesh in any position and will automatically cause the flutes on the two drums Vto register. Alternatively there may for example be twice as many gear teeth as there are flutes, though some care is then required to ensure that the flutes register.

An ejector is provided to remove from the stream of tested cigarettes any that are regarded as being unsatisfactory. The ejector may comprise an air jet positioned, for example, adjacent to the end of one of the flutes of the drum 9, to blow cigarettes endwise out of the stream, and operated by a valve controlled from the signal produced by the suction transducer.

The machine is positioned at the output from a cigarette-making machine, which may include plug-assembler apparatus for making filter tip cigarettes, and operates continuously to separate unsatisfactory cigarettes from the stream produced by the cigarette-making machine in the manner which will now be described.

The cigarettes on the conveyor 7 are picked up by suction on to the drum 8 and carried around to the carrier drum 1, at which point suction to the utes of the drum 8 is cut off and they are held in the flutes in the carrier drum 1 by the guide rails 10. Rotation of the drum 1 carries each cigarette in succession under the guide 10 into the testing position, and as it approaches this position it is gradually covered by one of the flutes 13 0f the closure drum 2. At the same time the passage 12 in the closure drum cornes into register with the port 50, thereby connecting the flute 13 with suction. In the testing position, as can be seen in FIG. 2, suction is applied to the zone around the middle of the cigarette between the formers 27 and 28 and between the discs 18 and 19. Some air flows into this zone from atmosphere in the air rings around the cigarettes under the ribs 16 and 26, but since free ow under these ribs is not possible and since the suction source is large, the pressure in this zone is reduced below atmosphere. As a result of this reduced pressure some air may flow from the interior of the cigarette through the wrapper.

If, as is the usual case with cigarettes, the Wrapper is somewhat air-pervious then there is always some air ow even with cigarettes that are regarded as being satisfactory. However, if the wrapping of the cigarettes is leaky owing, for example, to holes in the Wrapping or owing to an excessively porous wrapping or (in the case of mouthpiece cigarettes) owing to a poor joint, then this airflow is increased. The effect of this increased airflow through the wrapper is to reduce the pressure inside the cigarette. The lling of a cigarette has a relatively low resistance to airflow and thus the pressure at the ends of the cigarette in the regions of the end rings 24 and 2S and the end pieces 32 and 33 is reduced. This reduction of pressure at the end is sensed by the transducer 40, which causes the leaky cigarette to be ejected.

More precisely, the suction in the zone around the cigarette at the testing position produces an air ow, from atmosphere to the zone via the annular space 22, 30 (FIG. 2), through wedge-shaped leakage passages 35A (see FIG. 4) into a small space at the right-hand end of the cigarette (FIG. 2) communicating with the passage 46, through the interior of the cigarette and radially out through the wrapper of the cigarette. The suction pressure sensed by the transducer 40 via the passages 45 and 46 depends upon the air ow through the wrapper of the cigarette since the air flow path from atmosphere to the end space (communicating with the passage 4S) comprises the predetermined leakage path through the wedge-shaped openings 35A formed between the ribs 26 and 16 at the testing position. In the event of a cigarette wrapper at the testing position having a hole, the increased air flow which this hole allows produces an increased pressure drop from atmosphere to the end space, and the transducer 40 responds to this increased pressure drop to cause the cigarette to be ejected.

Continued rotation of the carrier drum 1 exhausts the suction transducer to the air space 22 through the passages 44 and 47, in readiness for the next cigarette, and carries the cigarette under the guide 11 to the return drum 9 which returns the cigarettes to the conveyor 7.

FIGS. 5 and 6 show diagrammatically a different tester according to this invention. To start with it will be seen that the carrier drum 60 and closure drum 62 are of the same diameter (and accordingly rotate at the same speed). Furthermore, the closure dmm lies more to one side of the carrier drum, rather than almost directly above as in the previous example, though in this case the closure drum is still held against the carrier drum by gravity, being free to swing downwards about the horizontal axis of a hollow shaft 64 by which a housing 66 is pivotally mounted on a stationary framework member 68.

As in the previous example, the housing carries the closure drum. Suction is fed into the closure drum through the hollow shaft 64, via a passageway 70 leading to a chamber 72. This chamber communicates with a space 74 in the closure drum via an opening 76 in a wall 78 of a stationary member which in this case has a boss portion 79 secured by a key 80 to a shaft 82 carried by the housing 66. The wall 78 has a narrow slot 84, corresponding to the slot S0 in the previous example, through which suction is connected to the annular space around the cigarette at the testing point between the two drums. The drums in this case have flutes and sealing ribs (not shown), as in the previous example.

As shown diagrammatically in FIG. 6, the closure drum has an inner sleeve part 86 which is joined to the peripheral part of the drum by an end wall 88. The drum is rotatably mounted on the shaft 82 by means of a central ball bearing 90 lying between the shaft and the sleeve part 86 of the drum. The inner race of the ball bearing is clamped between a shoulder 92 on the shaft and a spacer sleeve 94, the Whole assembly being secured by a nut screwed on to a narrow threaded end portion 98 of the shaft.

The single central ball bearing 90 allows the drum a slight amount of freedom to tilt about a line 100 (see FIG. 5) parallel to a common tangent to the two drums. This ensures that the closure drum makes rolling contact with both ends of the carrier drum. Swivelling of the closure drum about a line 102 (FIG. 5) passing through the axes of rotation of both drums and lying at right angles to both these axes (and to the line 100) is prevented by two rollers 104 which lie on opposite sides of the closure drum axis, with their axes passing through the closure drum axis, and bear on the end wall 83 of the closure drum. FIG. 6 shows one of these rollers, While FIG. 5 shows the positions of both in dotted outline.

As shown in FIG. 6,.each roller 104 is mounted on a pin 106 passing through the forked end of a carrier part 108 which is secured in a bore in the housing 66 by a grub screw 110. Where it lies within the bore in the housing, the carrier part 108 is of circular cross-section, except that it has a at chordal face 112 which is engaged by the end of the grub screw. The axial position of the carrier part can be adjusted as necessary.

The ball bearing 90 may be a conventional deepgrooved ball bearing with sufficient clearance between the races and balls to allow the drum the desired slight freedom of tilt about the line 100. Alternatively, in place of the ball bearing there may be a self-aligning bearing, though in this case it may be necessary to provide stops to prevent any excessive Swivelling about the line 100 when the closure drum is moved away from the carrier drum for inspection or for any other reason.

The rollers 104 may be mounted on the pins 106 via ball or roller bearings. Alternatively the rollers themselves may be the outer races of ball or roller bearings.

To allow the closure drum the desired slight freedom of Swivelling movement about the line 100, it will be appreciated that there should be a slight clearance between the drum and the inner stationary parts at areas 114 and 116 (see FIG. 6).

In carrying out this invention it is possible in principle to feed the suction through the carrier drum, instead of through the closure drum. In this case suction may be used to hold the cigarettes in the flutes in the carrier drum, and the guide rails may be omitted. A further possibility is that, instead of suction, compressed air may be fed (via either the carrier drum or the closure drum) to a space communicating with one or both ends of the cigarette, at the testing point, while a space around the cigarette (i.e., the suction space in the preferred examples) is at atmospheric pressure; in this case, if the compressed air is delivered via a restrictor then there will be a detectable drop in pressure in the end space in the lcase of a leaky cigarette wrapping, and this pressure drop may be used to activate the ejector mechanism.

As shown in FIG. 5, the single conveyor 7 in FIG. l may be replaced by two conveyors 118 and 120. A suction drum 122 transfers the cigarettes from the conveyor 118 to the carrier drum, and a suction drum 124 transfers the cigarettes, after testing, for the carrier drum to the conveyor 120.

What we claim as our invention and desire to secure by Letters Patent is:

1. A tester for testing the wrappings of ycigarettes and similar articles by creating a pressure difierential radially across each wrapping to detect whether or not the wrapping lis leaky, comprising a rotary carrier drum which has circumferentially spaced axial flutes and which carries the cigarettes, one in each flute, from an input conveyor to an output conveyor, and including seal portions at the ends of the fiutes to restrict communication between the interior and exterior of the cigarettes via the open ends of the cigarette wrappings during testing, characterized in that the cigarettes are carried by the carrier drum past a co-operating closure drum which rotates adjacent to the carrier drum, about an axis parallel to that of the carrier drum and at the same peripheral speed, and has circumferentially spaced closure parts which register with the fiutes on the carrier drum and are so shaped that each closure part of the closure drum co-operates with a flute of the carrier drum to define momentarily a chamber around the cigarette, terminated substantially at the ends of the cigarette by additional seal portions defined partly by the carrier drum and partly by the closure drum to restrict communication between the interior and exterior of the cigarette via the open ends of the cigarette wrapping, said closure drum being carried by a housing pivoted about an axis parallel to the axes of rotation of the drums, so that the closure drum can be swung away from the carrier drum when necessary, said closure drum being rotated through intermeshing gear Wheels mounted respectively on the closure drum and carrier drum, in which the number of gear teeth on each gear wheel equals the number of fiutes in the corresponding drum.

2. A tester for testing the wrappings of cigarettes and similar articles by creating a pressure differential radially across each wrapping to detect whether or not the wrapping is leaky, comprising a rotary carrier drum which has circumferentially spaced axial flutes Iand which carries the cigarettes, one in each fiute, from an input conveyor to an output conveyor, and including seal portions at the ends of the flutes to restrict communication between the interior and exterior of the cigarettes via the open ends of the cigarette wrappings during testing, characterized in that the cigarettes are carried by the carrier drum past a co-operating closure drum which rotates in rolling contact with the carrier drum, about an axis parallel to that of the carrier drum and at the same peripheral speed and has circumferentially spaced closure parts which register with the iiutes on the carrier drum and are so shaped that each closure part of the closure drum co-operates with a flute of the carrier drum to define momentarily a chamber around the cigarette, terminated substantially at the ends of the cigarette by additional seal portions defined partly by the carrier drum and partly by the closure drum to restrict communication between the interior and exterior of the cigarette via the open ends of the cigarette wrapping, said closure drum being carried by a housing pivoted about an axis parallel to the axes of rotation of the drums, which are horizontal so that said closure drum can be swung from a Iposition in which it is held by gravity into rolling contact with the carrier drum, including means on said carrier drum for defining an end space adjacent lto one end of each cigarette, and means for monitoring the pressure in each end space in turn at a testing position, said end spaces being isolated from said chamber by said additional seal portions comprising two axially spaced ribs on said closure drum, said ribs on said drums being aligned so as to define between them a short annular space around the cigarette at the testing position, which annular space is vented to atmosphere, the ribs between the annular space and the end space being in the form of a partial barrier defining a pair of wedge-shaped gaps providing a predetermined leakage path between said end space and said annular space.

3. A test-er according to claim 2, wherein a plurality of apertures is provided in the rib on said carrier drum located between said annular space and said end spaces, each of said apertures -being located between said end spaces at positions intercepted by said means monitoring the pressure in said end spaces so that said monitoring means is connected to the atmospheric pressure in said annular space alternately with connection to said end spaces.v

4. A tester for testing the wrappings of cigarettes and similar articles by creating a pressure differenti-al radially across each wrapping to detect whether or not the wrapping is leaky, comprising a rotary carrier drum which has circumferentially spaced axial utes and which carries the cigarettes, one in each iiute, from an input conveyor to an output conveyor, and including seal portions at the ends of the fiutes to restrict communication between the interior and exterior of the cigarettes via the open ends of the cigarette wrappings during testing, characterized in that the cigarettes are carried by the carrier drum past a co-oper-ating closure drum which rotates in rolling contact with the carrier drum, about an axis` parallel to that of the carrier drum and at the same peripheral speed and has circumferentially spaced closure parts which register with the fiutes on the carrier drum and are so shaped that each closure part of the closure drum cooperates with a flute of the carrier drum to define momentarily a chamber around the cigarette, terminated substantially at the ends of the cigarette by additional seal portions defined partly by the carrier drum and partly by the closure drum to restrict communication between the interior and exterior of the cigarette via the open ends of the cigarette wrapping, said closure drum being carried by a housing pivoted about an axis parallel to the axes of rotation of the drums, which are horizontal so that said closure drum can be swung from a position in which it is held by gravity into rolling contact with the carrier drum, including means on said carrier drum defining an end space communicating with one end of the cigarettes carried on said carrier drum, and means for monitoring the pressure in said end space, said additional seal portions including means forming a pair of wedge-shaped gaps between said end space and atmospheric pressure at a testing position providing a predetermined leakage path t0 said end space.

5. A device for testing the wrappings of cigarettes and similar articles by creating a pressure differential radially across each wrapping to detect whether or not the wrapping is leaky, comprising a carrier drum formed with circumferentially spaced axial flutes for receiving one article in each iiute; means for rotating the carrier drum about its axis; a closure drum mounted adjacent to the carrier drum, with its axis parallel to that of the carrier drum, and arranged to rotate with the same peripheral speed as the carrier drum; means for connecting to a source of suction a first annular space defined around each article in turn at a testing position by the adjacent parts of the two drums; means on the two drums for defining an end space adjacent to one end of each article in turn at the testing position; and means for monitoring the pressure in the end space; the end space being isolated from the first annular space by a seal comprising two axially spaced ribs on the carrier drum and two axially spaced ribs on the closure drum, the ribs on the two drums being aligned whereby they define between them a short second annular space around the article at the testing position, which second annular space is vented to atmosphere, the ribs between the second annular space and the end space serving as a partial barrier but at the same time defining a pair of wedge-shaped gaps serving as a predetermined leakage path between the end space and the second annular space.

6. A tester for testing the wrappings of cigarettes and similar articles by creating a pressure differential radially across each wrapping to detect whether or not the wrapping is leaky, comprising a rotary carrier drum which has circumferentially spaced axial llutesy and which carries the cigarettes, one in each ute, from an input conveyor to an output conveyor, and including seal portions at the ends of the flutes to restrict communication between the interior and exterior of the cigarettes via the open ends of the cigarette wrappings during testing, characterized in that the cigarettes are carried by the carrier drum past a co-operating closure drum which rotates adjacent to the carrier drum, about an axis parallel to that of the carrier drum and at the same peripheral speed and has circumferentially spaced closure parts which register with the flutes on the carrier drum and are so shaped that each closure part of the closure drum co-operates with a flute of the carrier drum to dene momentarily a chamber around the cigarette, terminated at or near the ends of the cigarette by seal portions dened partly by the carrier drum and partly by the closure drum to restrict communication between the interior and exterior of the cigarette via the open ends of the cigarette Wrapping, said closure drum being in rolling contact with both ends of the carrier drum and being rotatably mounted on a central bearing which allows the closure drum to swivel slightly about an axis parallel to a common tangent to the two drums to insure that the closure drum does touch both ends of the carrier drum.

7. A tester according to claim 6 in which swivelling movement of the closure drum about an axis passing through the axes of rotation of the two drums and at right angles to these axes is prevented by two rollers which are mounted about stationary axes of rotation lying substantially radially with respect to the closure drum, and which roll against an end face of the closure drum, the rollers being on opposite sides of the closure drum axis.

8. A tester according to claim 6 in which the central bearing on which the closure drum is mounted is a ball bearing which allows a small amount of the desired swivelling movement, but not a substantial swivelling movement.

9. A tester for testing the wrappings of cigarettes and similar articles by creating a pressure differential radially across each wrapping to detect whether or not the wrapping is leaky, comprising a rotary carrier drum which has circumferentially spaced axial utes and which carries the cigarettes, one in each flute, from an input conveyor to an output conveyor, and including seal portions at the ends of the utes to restrict communication between the interior and exterior of the cigarettes via the open ends of the cigarette Wrappings during testing, characterized in that the cigarettes are carried by the carrier drum past a co-operating closure drum which rotates adjacent to the carrier drum, about an axis parallel t0 that of the carrier drum and at the same peripheral speed and has circumferentially spaced closure parts which register with the utes on the carrier drum and are so shaped that each closure part of the closure drum co-operates with a flute of the carrier drum to dene momentarily a chamber around the cigarette, terminated at or near the ends of the cigarette by seal portions defined partly by the carrier drum and partly by the closure drum to restrict communication between the interior and exterior of the cigarette via the open ends of the cigarette wrapping, a source of suction connected to the chamber around the cigarettes at the testing point between the two drums, and a pressure-sensitive device which detects the presence of a leaky cigarette wrapping by responding to the reduced pressure which is created in a space at one end of the cigarette owing to leakage through the Wrapping, said suction being derived from a suction space within the closure drum to which suction is fed through a pipe having its axis on the pivot axis of the housing carrying the closure drum, the closure drum having a radial hole which extends inwards from each closure part and, at the test point, registers with a hole in a Wall of a stationary member containing suction.

10. A tester according to claim 9 in which suction is lfed continuously to the interior of the closure drum through one or more of the radial holes as they sweep past a suction supply passage in a part of the housing extending along the periphery of the drum.

References Cited UNITED STATES PATENTS 3,266,295 8/1966 Williamson 73-38 3,270,551 9/1966 Schmalz 73-45.1 3,408,858 ll/1968 Keading et al. 73-45.2 3,426,582 2/1969 McArthur et al. 73-45.l 3,485,084 12/1969 Doerrnan 73-45.1

LOUIS R. PRINCE, Primary Examiner W. A. HENRY II, Assistant Examiner 

